Due to technical issues, this feature is currently unavailable, as of January 17, 2020. Please continue to check back for further updates
We have a great FAQ that explains how to transfer and will update as soon as the issues have been resolved. Have you checked this out yet?
https://turbotax.community.intuit.ca/community/importing-transfering/help/in-turbotax-online-how-do-i-transfer-my-information-personal-details-carry-forward-amounts-etc-from/00/873503